Can someone help me with some screen issues I am having?

I am having an issue with my X2, where the screen is completely non-responsive.

Model: C6606
Firmware: 4.3
Rooted: Yes

The screen stopped responding to touch. This problem is across the entire screen. The phone was not dropped.

After a factory restore, the screen was working for a few minutes and then went non responsive again. However, when it was working, the sensitivity was about a 3/10 and the screen had to be pressed much harder than usual to register the touch.

Now, if I turn the phone off and turn it back on, the screen will work with the very low sensitivity and then stop working again.

I believe there is a newer version of firmware than 4.3. However, both on the phone itself and when connected to my laptop, the Sony PC Companion says it is up to date. It did this both before and after rooting it.